This invention relates to a system and methods for monitoring of boundaries. More specifically, but without limitation, this invention relates to a security system that transmits vibrations along a waveguide and then senses the vibrations to detect, localize, and/or classify the vibration.
The prior art discloses a number of different means to detect intrusions or other disturbances in a fence or other boundary. One common method is to use taut wire systems. One example of a taut wire system is disclosed in U.S. Pat. No. 4,829,287 to Kerr et al. In such a taut wire system, sensors such as pressure sensors or strain gauges are used to sense changes in the tension of the wire. In this and other systems, because tension is being sensed, a number of sensors are required along the fence to ensure that an intrusion does not go undetected. If there is too great of distance between sensors, then added tension due to an intrusion may go unnoticed.
Prior art detection systems using geophones also work in a similar manner, wherein the number of geophones needed to detect a signal directly increases with the size of the area that is being secured. The present invention uses a waveguide to transmit vibrations thus does not require a large number of sensors. This reduces cost and/or increases the distance that can be covered.
Another type of system involves leaky coaxial cables. One example of a leaky coaxial cable system is disclosed in U.S. Pat. No. 4,879,544 to Maki et al. In such a system, two cables are run parallel to one another, one acting as a transmitter, the other acting as a receiver. When the radio frequency signal leaks from the transmitter cable to the receiver cable, a field is created between the two cables. The changes in the field are monitored to determine if an intrusion has occurred. If the cable is cut, then this type of system fails to work and requires repair.
Another type of system uses fibre optic cables. The fibre optic cables are attached to a fence. When the cable is cut or otherwise broken, an alarm occurs. Such a system is not useful for determining every type of intrusion, and once the cable is cut it will need to be replaced. The present invention provides for simplified repair or replacement which results in less cost and less down time.
Thus, it is a primary object of the present invention to provide a method and system for detecting, localizing, or classifying a disturbance that improves upon the state of the art.
Another object of the present invention is to provide for a method and system for detecting, localizing, or classifying a disturbance that effectively extends the range of an acoustic or vibration sensor thus reducing the number of sensors required.
A further object of the present invention is to provide a method and system for detecting, localizing, or classifying a disturbance that is easily repairable and minimizes down time.
Yet another object of the present invention is to provide a method and system for a security system that can be implemented either above ground or underground.
Another object of the present invention is to provide for a method and system for detecting, localizing, or classifying a disturbance that is compatible with irregularly shaped fences or other boundaries.
Another object of the present invention is to provide for a method and system for detecting, localizing, or classifying a disturbance that is flexible in implementation and application such that both large areas or small areas can be detected.
Another object of the present invention is to provide for a method and system for detecting, localizing, or classifying a disturbance that is reliable.
Another object of the present invention is to provide for a method and system for detecting, localizing, or classifying a disturbance that is low in cost.
These and other objects, features, or advantages of the present invention will become apparent from the specification and claims.
The present invention is directed towards a system and method of using a waveguide sensor system for applications that include, but are not limited to detecting, localizing, and classifying a disruption along a boundary. A particular application, described throughout, but to which the invention is not limited, is the use of the present invention in a security system. In a security system, the disruption that occurs along a boundary may be caused by an intrusion. The boundary can be associated with a security fence, but need not be.
According to one aspect of the present invention, a vibration detection and classification system includes a waveguide in operative contact with a boundary, at least one sensor for sensing vibrations, and a control circuit operatively connected to the at least one sensor. The control circuit can be adapted for detecting and classifying the vibrations to determine if the boundary has been crossed by an intruder.
Another aspect of the present invention relates to the case where the boundary is a fence. A vibration coupler is used to connect the fence with the waveguide. The vibration can be an arc-shaped band of metal and the waveguide can be a tensioned wire. The waveguide allows vibrational waves to be received and/or transmitted by the control circuit. Where the vibrational waves are received by more than one control circuit, the location of the disturbance can be determined through time estimation or other means. Thus, the present invention can provide for localization.
Another aspect of the present invention provides for a method of securing an area protected by a boundary. The method includes mechanically transmitting a vibration from a portion of the boundary to a waveguide, transmitting the vibration along the waveguide to a sensor, sensing the vibration at the sensor, determining at least one characteristic associated with the vibration, and using the at least one characteristic associated with the vibration to determine if the vibration is indicative of an intrusion. If an intrusion is detected, then the present invention provides for an alarm or an alert, the deployment of weapons systems, or other measures to be taken.
The present invention contemplates numerous applications and varying levels of complexities of security systems that can be implemented according to the present invention. For example, one application of the present invention is suitable to secure fences along national borders, military installations, airports, or other large areas. In such an application, more complex sensing systems and processing can be used for enhanced localization and classification of a disturbance. Additional alarm or alert systems can also be used in such a system. The present invention is also suitable for smaller and/or less sophisticated installations, including installations where localization of a disturbance is not required.